Thread-cutting device



Oct. 23, 1951 G. HAZELTON 2,572,143

' THREAD-CUTTING DEVICE Filed May 27, 1948 2 SHEETSSHEET l 79 660 ?65 HAZEL TO/V Patented Oct. 23, 1951 THREAD-CUTTIN G DEVICE George Hazelton, Leicester, England, assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application May 27, 1948, Serial No. 29,600 In Great Britain June 26, 1947 11 Claims. 1

This invention is concerned with improvements in thread cutting devices for shoe sewing or other types of thread handling machines. As hereinafter described one convenient construction of thread cutting device in accordance with the invention is arranged to cut one leg of a loop of thread drawn up through a work piece by a straight hooked needle of a chainstitch shoe sole sewing machine similar to that disclosed in United States Letters Patent No. 710,612, granted October 7, 1902, upon application of E. P. Richardson.

One of the various objects of the present invention is to provide an improved thread cutting device by means of which one ofa pair of lengths of thread lying relatively close together may quickly and accurately be severed while the other is deflected with certainty out of the path of the cutting edge of a knife mounted on the machine.

The illustrative device, hereinafter described, comprises a thread cutting knife having one sharpened edge and a pointed end arranged to pass in the direction in which its tapered end points between two legs of a loop of thread lying relatively close together and thread guiding means arranged to move with the knife into engagement with the legs of thread and relatively to the knife to deflect them for operation of the knife. The knife, according to this feature, has formed on one side only of it a cutting edge behind its point and the thread guiding means comprises a pair of yielding members, one at each side of the knife, arranged to deflect both legs of thread against the knife, one member pressing one leg against the knife edge and the other member pressing the other leg against the blunt edge of the knife and retaining control of it while the cutting edge cuts through the first mentioned leg. The knife and guiding members normally occupy a position relatively remote from the sewing point and, when it is desired to sever the thread, are moved in a direction to operate on the thread by an operating lever.

These and other features of the invention consist in the devices, combinations and arrangements of parts hereinafter claimed, which together with the advantages obtained thereby will readily be apparent from the following detailed specification, taken in connection with'the accompanying drawings, in which,

Fig. 1 is a front elevation of part of a straight needle chain stitch shoe sole sewing machine having a thread cutting device embodyingthe present invention;

. .Fig. 2 is a frontelevation of part of the illustrative thread cutting device shown on a larger scale than in Fig. 1;

Fig. 3 is a section on the line III-III in Fig. 2;

Fig. 4 is a plan view, in the direction of the arrow, of the parts shown in Fig. 2;

Fig. 5 is a detail plan View of a knife and adjustable stop member shown in Figs. 3 and 4;

Fig. 6 is a left-hand side elevation of the illustrative thread cutting device;

Figs. 7, 8 and 9 are plan views illustrating the cutting of thread by the illustrative device;

Fig. 10 is a sectional view on an enlarged scale of the thread cutting device taken along the line XX of Fig. 9; and

Fig. 11 is a similar view of the same device taken along the line XI--XI of Fig. 9.

The illustrative thread cutting device comprises a pointed knife mounted for swinging movement in the direction of taper of the point on the knife toward andfrom a loop of thread carried by a hook needle of a shoe sewing machine. The knife is mounted on a vertical bracket I secured to the left-hand side, viewing the machine from the front, of the upright referred to as the upright 6 in the Richardson patent near the front of the sewing machine disclosed therein. The bracket 1 has extending from it a vertical plate-like portion 3. The platelike portion 3 of the bracket I has formed in it a slot 5 extending at an angle of about thirty degrees to the Vertical. Arranged in the slot is a roll 1 (Figs. 1 and 6) mounted on a horizontal stud 9. To limit downward movement of the roll I, an adjusting screw l l in the plate-like portion 3 of the bracket 1 extends upwardly into the bottom of the slot 5. The stud is secured in the upper end portion of a knife bar [3 having at its lower end a pair of oppositely disposed lugs [5. Each lug l5 has a slot, through which slots pass clamp screws ll threaded into similar lugs on the upper end of a knife holder [9 which forms a continuation of the knife bar l3. When the clamp screws I! are loosened the knife holder 19 may be adjusted forwardly or rearwardly of the machine on the knife bar 13.

The knife bar i3 has pivotally'connected to it just above the lugs l5 the end of an operating lever 2| which extends across the front of the machine. The operating lever 2| is pivoted at its other end to a stud 23 secured in a bracket 25 fixed to the right-hand side of the machine frame. The right end of the operating lever 2! is pivotally connected to an adjustable link 25, the upper end portion of which is pivotally connected to the lower endfiof a plunger 21 of a sole- 3 mid, indicated at 29, attached to the machine frame and controlled by a switch 38. To hold the roll I at the upper end of the slot 5, a tension spring 3! is connected to the left-hand end of the lever 2i and to the plate-like portion 3.

Pivotally connected to the lower end of the knife holder is by a horizontal bolt 33 is a knife block 35. The knife block 35 has an arm 31 engaging the front face of the knife holder and has formed in it an arcuate slot 39, concentric to the axis of the bolt 33 through which slot passes a screw 4! threaded into the knife holder I 9. When the screw 4! has been loosened the knife block 35 may be adjusted angularly about, the bolt 33 to bring the cutting position of the knife closer or further away from the work.

The knife block 35 extends downwardly and to the right from the bolt 33 and has formed in its underside a groove 43 (Fig. 3). In this groove is secured the left end of the pointed thread cutting knife, indicated at 45. Theknife 45 is secured in the groove 43 by a screw 41 passing downwardly through the knife block and threaded into the knife. The screw 41 passes through a slot in the knife block 35 so that the knife and screw may be adjusted towards or from the needle 49 of the machine and therefore towards or from a loop of thread extending from the needle to a work piece in the machine. The screw t! at its upper end has on it a square head, extending above the knife block, by which the screw may be tightened and a flange 5| acting within a recess 53 in the block against which the clamping action of the screw is exerted. w 7 v Adjustment of the knife 45 in the knife block 35 in a direction towards the needle (i. e. toward the right) is limited by an adjustable U-shaped stop member 55 secured to the rear face of the knife block 35. The stop member 55 has in it a slot to receive a screw 51', threaded into the knife block, so that the stop member 55 may be adjusted on the knife block. The stop member 55 has a portion 5a, extending forwardly below the knife block, which has on it a shoulder 5| (Fig. 5) arranged to be engaged by a shoulder 53 on the knife to limit movement of the knife in a direction towards the needle 49. The stop member 55 also has a portion 65 extending forwardly above the knife block. The portion 85 of the stop membar above the knife block extends partly over the recess 53 in the knife block and prevents, by its engagement with the flange 5| on the screw 47, the screw from being removed from the knife block. When the knife is removed for sharpening or renewal, the screw remains in the knife block ready to be used in reclamping the knife with accuracy.

To deflect the legs of a needle loop laterally until they are brought into a position where the point of the knife will enter between them according to a feature of the invention, the knife block 35 has extending from its right face a pair of lugs 61, 51 lying one behind the other, viewing the machine from the front. Pivoted to the lugs 6'1, 61 by pins 69, 69, are the left channeled ends of two thread engaging fingers H, 13 (see Fig. To move the fingers toward and from the knife, they are connected together by a slot-and-pin joint 14 between their pivots so that if one finger is moved the other finger moves simultaneously in the opposite direction. The left face of the front finger H is engaged in front of its pivot by a spring-pressed plunger 15 in the knife block so that the right-hand end portions of the fingers, which lie above and below the knife (see Fig. 11)

are yieldingly urged towards and substantially into contact with each other to cover the knife almost completely.

The knife 45 lies between the fingers and its right-hand end portion is beveled in opposite directions to provide a central point. The beveled edge I! of the knife at the front of the point has a sharpened edge and the rearward beveled edge 19 is unsharpened and blunt to deflect the rear leg of the needle loop rearwardly. The edges of the two fingers curve outwardly as shown at 8| to the right so that a more or less V-shaped notch is provided between them to deflect and press the legs of the loop against the edges of the knife and the length of the knife is such that its point lies centrally in this notch. To cover the edges of the knife more effectively the right end of the rear finger 73 is held against the rear edge of the knife by the aforesaid spring-pressed plunger '15 and the rear edge of the front finger H has a recess 83 which clears the knife edge. This. ces m ha e in it. a o led fe t pad or u riq ne he. cutt n e th nife- Wh n the ll strative h ad cutting de ce is n ts r ised mperative po i on rem e f the sewing point, the right ends of thefingers ll, '13 are out of the path of the work so that no interferences occur. After the machine has stopped the operator presses inwardly the button of switch 30 and energizesthe solenoid which operates the lever 2|. When the lever Zl is operated the fingers and the point of the knife are moved along a curved path in the general direction of the knife point to their fully actuated positions (see dotdash lines of Fig. 1) determined by the adjustable screw l I, the right-hand end portions of the fingers and the point of the knifev being a little above the upper surface of the, work on the right of the needle path. The movement of the fingers and the knife causes the ends of the fingers to engage the needle loop at the sides of its two legs extending from the needle to the work, one. leg of the loop passing downwardly in front of the needle and the other behind the needle. The legs are separated by the needle at the upper end of the loop and meet at the hole in the work piece from which they emerge. There is therefor a small space between the legs which decreases in size from the needle to the work, As th'e'fingers approach the loop they engage the outer sides of the loop and, if necessary, move, the legs of the loop slightly until they are brought into such position that the knife point will enter between them. As the fingers and knife are moved further the fingers are openedslightly by the pressure of the legs of the loopagainst them and the rear leg of the loop then wedges between the rear finger l3 and the unsharpened or blunt rear edge 19 of the knife and the front leg of the loop is engaged between the front finger H and the sharpened edge 7?; severing the thread.

In Fig. 7 the fingers "H and I3 are shown just before they engage the legs of the loop, the gap between which is shown as being slightly forward of the point of the knife. In Fig. 8 the fingers are shown as having engaged the legs of the loop and movedthem rearwardly to bring them into line with the point of the knife. Fig. 9 shows the fingers slightlyspread apart by the legs of the loop and the point of the knife about to enter the loop. 7

The fingers H, 13 and knife 45 may be adjusted as a unit with great accuracy forwardly or rearwardly relatively to the need and loop of thread by adjusting the knife holder on the knife bar. The position of'thelfingers Tl, Band knife-45 laterally of the machine relatively to the needle and loop of thread when in their lowered position, may also be adjusted by means of the adjustable screw II and the angular and heightwise position of the fingers and knife may be adjusted by shifting the knife block 35 on the knife-holder [9 about its pivot bolt 33. With this arrangement the knife and fingers may be adjusted in different directions at an angle to each other. 7

To prevent the illustrative thread cutting device from being operated when the machine is in operation, according to a further feature of the invention, a cutout 81 is provided between the switch 39 and source of supply of electric current. The cutout is operated by a main driving clutch treadle rod 89 whichhas projecting from it an. arm 9| which operates the cutout. When the treadle rod is moved downwardly to cause the machine to be operated the cutout is opened and the supply of current to the switch is prevented, so that, even if the switch is closed While the machine is in operation, no movement of the thread cutting device will occur.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

1. A device for cutting and controlling a loop of thread in a shoe sewing machine, having a pointed thread cutting knife mounted for movement in the direction of its point toward and from a loop of thread, in combination with means movable with the knife toward and from the loop of thread to deflect the thread of the loop against both edges of the knife at opposite sides of. its

' point.

2. A device for cutting and controlling a loop of thread in a shoe sewing machine, having a pointed thread cutting knife mounted for movement in the direction of its point toward and from a loop of thread, in combination with a member mounted for movement with the knife toward and from the loop of thread and relatively to the knife to press one leg only of the loop of thread against the cutting edge of the knife as it moves toward the thread.

3. A device for cutting and controlling a loop of thread in a shoe sewing machine, having a pointed thread cutting knife formed with one sharpened and one unsharpened edge at sides of the point and mounted to swing in the direction of its point toward and from a loop of thread carried by the machine, in combination with a member mounted for movement with the knife and relative to the knife to press one leg only of the loop against the sharpened edge of the knife as it swings toward the thread, and a second member similarly mounted to deflect the other leg of the loop against the unsharpened edge of the knife while the sharpened edge cuts the thread.

4. A device for cutting and controlling a loop of thread in a shoe sewing machine, having a pointed thread cutting knife formed with one sharpened and one unsharpened edge at the sides of its point and mounted for swinging movement in the direction of its point toward and from a loop of thread carried by the machine, in combination with a member mounted for movement with the knife and relative to the knife to press one leg only of the loop against the sharpened edge of the knife as it swings toward the thread, and a second member similarly mounted to deflect the other leg of the loop against the unsharpened edge of the knife while the sharpened edge cuts the thread, said members being corlnected together by a pin-and-slot connection to cause them to move simultaneously in opposite directions relatively to the knife.

5. A device for cutting and controlling a loop of thread in a shoe sewing machine, having a pointed thread cutting knife formed with one sharpened and one unsharpened edge and mounted to swing-toward and from a loop of. thread carried by the machine, in combination with a member mounted to move with the knife and to press one leg only of the loop against the sharpened edge of the knife as'it swings toward the thread, and a second member similarly mounted to deflect the other leg of. the loop against the unsharpened edge of the knife while the sharpened edge cuts the thread, said members being connected together to cause them to move simultaneously away from the knife when engaging the loop of thread and being yieldingly actuated to cover-'the-knife when disengaged fromthe thread.

6. In a device for cutting and controlling a loop of thread in a shoe sewing machine having a treadle rod arranged to be moved to cause the machine to be operated, the combination with a thread cutting knife, of means for actuating the knife toward and from the loop of thread comprising an operating lever, an electrical solenoid, a switch for controlling the solenoid and a cutout operated by the treadle rod for opening the cir-* cuit to the solenoid when the treadle rod is moved to operate the machine.

'7. In a device for cutting and controlling a loop of thread in a shoe sewing machine having a treadle rod arranged to be moved to cause the: machine to be operated, the combination with a. pointed thread cutting knife, of means for actuating the knife in the direction of its point toward and from the loop of thread comprising an operating lever, a bar on which the knife is carried connected to the operating lever and means for adjusting the position of the knife on. the bar in different directions at an angle to each other.

8. In a device for cutting and controlling a loop of thread in a shoe sewing machine having;

a treadle rod arranged to be moved to cause the machine to be operated, the combination with apointed thread cutting knife, of means for actuating the knife in the direction of its point toward and from the loop of thread comprising an operating lever, a bar on which the knife is carried connected to the operating lever, a knife holder on the knife bar to enable the knife to be adjusted in one direction, and. a knife supporting block pivotally mounted on the knife holder to enable the knife to be adjusted in another direction on the knife bar by angular movement of the block on the holder.

9. In a device for cutting and controlling a loop of thread in a shoe sewing machine having a treadle rod arranged to be moved to cause the machine to be operated, the combination with a thread cutting knife, of means for actuating the knife toward and from the loop of thread comprising an operating lever, a bar on which the knife is carried connected to the operating lever, a block for supporting the knife on the'bar, and means for securing the knife on the block in adjusted position, comprising a stop member formed with a shoulder to limit the adjusting movement of the knife toward the loop of thread in the machine. I

10. In a device for cutting and controlling a leap; of; thread;v iii-Pal shoe": sewingg machine havinga. treadle. rod; arranged to be;movect. to cause: the. machine t0 be operated; the;-- combination with; a thread cutting knife, of;:'means;for actuating-the knife toward: and: from the. loop; of threaclf comprising: an, operating; lever; a; bar: on; which; the knife is; carried; connected; to: the operatingslevex: a knifeablock for; supportingihe knife on; the bar; and; means for. adjustabl-yrsecuring-i the knife'on the phloek; comprising a. screw engagihgthe; knife amia Jr-shaped; stop member; formechadmnmend with: atshoulder 'to limit the; adjusting mcrvement of:- the; knife towar.cl;the;loop;of thread. anchaixthe.

otherlend tam-retain the: screw in.,pnsitionz on the knife blockv when the-.knifefis memeved-ltherefmm;

11; In; a; device: for: cutting; amiucontro'llingj a loop of 5 thread; ima shoe; sewing; machine; having attreadle rod: arrangediQ-be: moyedjo-eaiusa-the machinetn be operated, the; combination with a; thread cutting; knife; of; means; for: actuating; 9.0

the: kniieatoward. and from; the: loop: of: threzui comprising: anzape'rating lever; abraeket havin'gza;

REFERENCES CITED Thefollowing references are of recordih the file ef this' patent:

UNITED. STATES-1 PATENTS, 

